1. Field of the Invention
This invention relates to methods and apparatus for the inspection for faults in conduits such as underground pipelines. More particularly, it deals with methods and apparatus for illuminating the interior sidewalls of the conduits for use with said inspection apparatus.
2. Background of the Invention
Closed circuit television has recently been used for sewer inspection and with grouting apparatus for making repairs. With closed circuit television, location of leaks, points of infiltration, paved-over manholes, pipeline breaks, and lost articles can be accomplished without the disadvantages accompanying the digging up of the pipeline.
A major problem in the use of cameras in a pipeline is satisfactory illumination of the interior pipeline wall which will allow the camera to obtain a satisfactory closeup view of the wall. In the past, high intensity light sources such as quartz lamps have been used to give bright light in the visible range for use with a conventional camera. These lamps are undesirable because of the large amount of heat generated.
Lower power light sources have been used with large parabolic reflectors to concentrate the light in the desired locations on the pipeline sidewalls. These systems, however, are bulky and in some cases too large to be used in smaller diameter pipelines. Also, since the reflectors are generally fixed, a different light assembly must be used for each diameter of pipeline to be inspected.
This invention provides a light assembly for use in a pipeline inspection system wherein the light assembly has low energy light sources, and the assembly also has an electrical circuit which supplies electrical current to the light sources when the voltage across the sources is equal to or below a predetermined value, and which interrupts the electrical current when the light source voltage exceeds the predetermined value.
The invention also provides a light assembly for use with a pipeline inspection system and having a cylindrical body with a central bore for receiving the inspecting camera of the pipeline inspection system; and also having light sources located in one end of the cylindrical body for providing illumination for the inspecting camera.
The invention further provides a light assembly which has low power requirements, and which is suited for pipeline inspection use in a sewer line environment.
The invention also provides a light assembly for use as a universal source of illumination for the inspection of a wide range of pipeline sizes.
The invention further provides a light assembly which can easily be mounted on and removed from the camera of a pipeline inspection system.
The invention also provides a light assembly for use in underground conduits and having a current interrupting circuit which provides a simple and certain method for setting and holding the voltage across a plurality of light sources in the light assembly at an optimum value for maximum light output and minimum degradation to the life of the light sources.